Synthesis and Structure-Activity Relationships of a Series of Aporphine Derivatives with Antiarrhythmic Activities and Acute Toxicity

Crebanine ameliorates ischemia-reperfusion brain damage by inhibiting oxidative stress and neuroinflammation mediated by NADPH oxidase 2 in microglia

BACKGROUND

The urgent challenge for ischemic stroke treatment is the lack of effective neuroprotectants that target multiple pathological processes. Crebanine, an isoquinoline-like alkaloid with superior pharmacological activities, presents itself as a promising candidate for neuroprotection. However, its effects and mechanisms on ischemic stroke remain unknown.

METHODS

The effects of crebanine on brain damage following ischemic stroke were evaluated using the middle cerebral artery occlusion and reperfusion (MCAO/R) model. Mechanism of action was investigated using both MCAO/R rats and lipopolysaccharide (LPS)-activated BV-2 cells.

RESULTS

We initially demonstrated that crebanine effectively ameliorated the neurological deficits in MCAO/R rats, while also reducing brain edema and infarction. Treatment with crebanine resulted in the up-regulation of NeuN+ fluorescence density and down-regulation of FJB+ cell count, and mitigated synaptic damage. Crebanine attenuated the hyperactivation of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 2 (NOX2) by downregulating NADP+ and NADPH levels, suppressing gp91phox and p47phox expressions, and reducing p47phox membrane translocation in Iba-1+ cells. Additionally, crebanine reduced the quantity of Iba-1+ cells and protein expression. Correlation analysis has demonstrated that the inhibition of NOX2 activation in microglia is beneficial for mitigating I/R brain injuries. Moreover, crebanine exhibited significant antioxidant properties by down-regulating the expression of superoxide anion and intracellular reactive oxygen species in vivo and in vitro, and reducing lipid and DNA peroxidation. Crebanine exerted anti-inflammatory effect, as evidenced by the reduction in the expressions of nitric oxide, interleukin 1β, tumor necrosis factor α, interleukin 6, and inducible nitric oxide synthase. The effect of crebanine was achieved through the suppression of nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinases (MAPK) signaling pathway. This is supported by evidence showing reduced NF-κB p65 promoter activity and nucleus translocation, as well as suppressed IκBα phosphorylation and degradation. Additionally, it inhibited the phosphorylation of ERK, JNK, and p38 MAPKs. Importantly, the anti-oxidative stress and neuroinflammation effects of crebanine were further enhanced after silencing gp91phox and p47phox.

CONCLUSION

Crebanine alleviated the brain damages of MCAO/R rats by inhibiting oxidative stress and neuroinflammation mediated by NOX2 in microglia, implying crebanine might be a potential natural drug for the treatment of cerebral ischemia.

Preparation and identification of isoquinoline alkaloids with ATP citrate lyase inhibitory activity from Dactylicapnos scandens

Three new isoquinoline alkaloids including a morphine derivative (1), two aporphine alkaloids (2-3), together with five known alkaloids (4-8) were obtained from the extract of Dactylicapnos scandens (D.Don) Hutch. (D. scandens). Their structures and absolute configurations were elucidated by extensive spectroscopic data analysis including HRESIMS, NMR and electronic circular dichroism (ECD) and ECD calculation. Compounds 1-8 were evaluated for ATP Citrate Lyase (ACLY) inhibitory activity through an enzymatic assay. Among them, 2 and 3 showed the high ACLY inhibitory activity with an IC50 value of 10.48 ± 1.59 and 10.89 ± 4.89 μM.

The anti-inflammatory and analgesic activities of 2Br-Crebanine and Stephanine from Stephania yunnanenses H. S.Lo

Ethnopharmacological relevance: Crebanine (Cre) and Stephanine (Step) are isoquinoline aporphine-type alkaloids that are extracted from Stephania yunnanenses H. S. Lo. Plants of the Stephania genus are often used for treatment of stomach pain, abdominal pain, and rheumatoid arthritis. Both Cre and Step exhibit strong activities but are also associated with a certain level of toxicity, 10,11-dibrominecrebanine (2Br-Cre) is a bromine-modified derivative of Cre that we prepared and tested in order to reduce toxicity and enhance efficacy. Aim of this study: To investigate the anti-inflammatory and analgesic effects of 2Br-Cre and Step based on previous research findings and explore the specific biological mechanisms involved. Materials and methods: The anti-inflammatory and analgesic effects of 2Br-Cre and Step were investigated using a range of experimental models, including xylene-induced ear edema, carrageenan-induced pleurisy, carrageenan-induced paw edema, the hot-plate test, the naloxone antagonism test and the acetic acid writhing test. A model of chronic constriction injury (CCI) of the sciatic nerve was also established to investigate therapeutic effects. A RAW264.7 cell model was established using lipopolysaccharide (LPS) to estimate the effects of these compounds on cytokines levels. Results: 2Br-Cre and step significantly inhibited ear edema, paw edema and presented anti-inflammatory activity in the pleurisy model by inhibiting leukocyte migration and nitric oxide (NO) production, and by reducing the levels of PGE2. 2Br-Cre and Step significantly increased the pain threshold of mice subjected to heat stimulation; the effect was blocked by naloxone, thus suggesting that the analgesic effects of 2Br-Cre and Step were mediated by opioid receptors. 2Br-Cre and Step inhibited the frequency of writhing and prolonged the latency of writhing, and reduced the abnormal increase in the levels of BDNF in the serum and brain, thus alleviating the pain caused by CCI. In addition, 2Br-Cre and Step significantly inhibited the production of several inflammatory cytokines (IL-6, IL-1β and TNF-α) by LPS-induced RAW264.7 macrophages (p < .01). Conclusion: 2Br-Cre and Step exerted remarkable anti-inflammatory and analgesic effects. As a structural modification of Cre, 2Br-Cre retains the anti-inflammatory and analgesic activity of Cre but with better efficacy. Consequently, 2Br-Cre should be investigated further as a lead compound for analgesia.

Crebanine induces ROS-dependent apoptosis in human hepatocellular carcinoma cells via the AKT/FoxO3a signaling pathway

Background: Hepatocellular carcinoma (HCC), as an aggressive cancer with a high mortality rate, needs high-efficiency and low-toxicity drug therapy. Natural products have great potential as candidate lead compounds for the development of new HCC drugs. Crebanine is an isoquinoline alkaloid derived from Stephania with various potential pharmacological effects such as anti-cancer. However, the molecular mechanism underlying crebanine-induced liver cancer cells apoptosis has not been reported. Here, we investigated the effect of crebanine on HCC and identified a potential mechanism of action. Methods: In this paper, we intend to detect the toxic effects of crebanine on hepatocellular carcinoma HepG2 cells through a series of in vitro experiments, including detecting the effects of crebanine on the proliferation of HepG2 cells using the CCK8 method and plate cloning assay, observing the growth status and morphological changes of crebanine on HepG2 cells by inverted microscopy; and using the Transwell method to determine the the effect of crebanine on the migration and invasion ability of HepG2 cells; using Hoechst 33258 assay to stain cancer cells, thus observing the effect of crebanine on the morphology of HepG2 apoptotic cells, and detecting the apoptotic state and level of HepG2 cells by flow cytometry; using ROS kit and JC-1 assay kit to detect the changes of reactive oxygen species and mitochondrial membrane potential of HepG2 The immunofluorescence assay was taken to verify whether crebanine had an effect on the expression of p-FoxO3a in cancer cells; the Wetern blot assay was also used to examine the effect of crebanine on proteins related to the mitochondrial apoptotic pathway and its effect on the regulation of the relative protein expression of AKT/FoxO3a axis; after this, NAC and AKT inhibitor LY294002 were used to cells were pretreated with NAC and AKT inhibitor LY294002, respectively, in order to further validate the inhibitory effect of crebanine. Results: It was shown that crebanine effectively inhibited the growth and capacity of HepG2 cells migration and invasion in a dose-dependent manner. Furthermore, the effect of crebanine on the morphology of HepG2 cells was observed through microscopy. Meanwhile, crebanine induced apoptosis by causing reactive oxygen species (ROS) burst and mitochondrial membrane potential (MMP) disrupt. We found that crebanine could down-regulate Bcl-2 and up-regulate Bax, cleaved-PARP, cleaved-caspase-3 and cleaved-caspase-9, but these effects were overturned by ROS inhibitor N-acetylcysteine (NAC). Crebanine also down-regulated p-AKT and p-FoxO3a, and the PI3K inhibitor LY294002 significantly enhances this effect. We also found that the expression of AKT/FoxO3a signaling pathway was ROS-dependent. As shown by Western blots, NAC could partially attenuate the inhibitory effect of crebanine on AKT and FoxO3a phosphorylation. Conclusion: Based on our results, our results suggest that crebanine, as a compound with potential anticancer activity, has significant cytotoxic effects on hepatocellular carcinoma,and it likely induces apoptosis via ROS in the mitochondrial pathway and simultaneously affects the biological function of HCC via the ROS-AKT-FoxO3a signaling axis.

The Anti-Sepsis Effect of Isocorydine Screened from Guizhou Ethnic Medicine is Closely Related to Upregulation of Vitamin D Receptor Expression and Inhibition of NFκB p65 Translocation into the Nucleus

Background

The anti-inflammatory application of Guizhou ethnic medicine in the Karst area of China is mainly based on folk medicine experience, and there has been a lack of systematic research, leading to limited application of Guizhou ethnic medicine.

Purpose

To evaluate the anti-inflammatory effects of compounds extracted from Guizhou ethnic medicine in the Karst area and investigate their molecular mechanisms.

Methods and Results

Preliminarily, the anti-inflammatory effects of 181 compounds extracted from Guizhou ethnic medicine were screened in lipopolysaccharide (LPS)-stimulated peritoneal macrophages and the 41 compounds with anti-inflammatory effects were selected. Then, these 41 compounds with anti-inflammatory effects were investigated for their druggability and 18 compounds were selected. Thirdly, compound Hx-150, named isocorydine, was selected as the candidate compound. In vitro and in vivo, isocorydine inhibited LPS-induced TNF-α and IL-6 release from LPS-treated mouse peritoneal macrophages. Isocorydine decreased TNF-α, IL-6, and IL-1β levels in the blood, lung, and spleen, and ameliorated lung tissue damage. Mechanistically, isocorydine had no effect on the mRNA expressions and protein levels of Tlr4, Myd88, and Traf6. Isocorydine also had no effect on the expression of RelA (encoding NFκB p65) mRNA, but inhibited phosphorylation of IκBα and NFκB p65 in the TLR4-mediated signaling pathway. Furthermore, isocorydine increased the cytoplasmic level of NFκB p65 and decreased its nuclear level in LPS-treated macrophages. Importantly, isocorydine upregulated Vdr mRNA (encoding the vitamin D receptor) expression and increased the nuclear VDR protein level.

Conclusion

Many compounds from Guizhou ethnic medicine had potential anti-inflammatory activities. Among them, isocorydine has a strong anti-sepsis effect, which is tightly related to its upregulation of VDR expression and inhibition of NFκB p65 translocation into the nucleus, leading to reduced pro-inflammatory cytokines release and protection for LPS-challenged mice.

Non-volatile constituents from Monimiaceae, Siparunaceae and Atherospermataceae plant species and their bioactivities: An up-date covering 2000-2021

The Monimiaceae, Siparunaceae, and Atherospermataceae, formerly included in the broad ''old'' Monimiaceae family, have long been known for their uses in traditional medicine and have proven to be rich sources of chemically diverse specialized metabolites with numerous potent biological and therapeutical properties. The progress made recently has expanded their phytochemistry and pharmacology albeit to different extents. This review focuses on the non-volatile constituents isolated from the three plant families during the last two decades and their emerging therapeutic potential. Based on the data collected from multiple databases without statistical analysis, approximately 93 components, of which 35 undescribed compounds including γ-lactones, alkaloids, terpenoids, flavonoids, and homogentisic acid derivatives, have been reported. Moreover, diverse biological activities of pure isolated compounds such as anticancer, antioxidant, antiparasitic, antiviral, and antibacterial activities have been evidenced. Besides offering new important perspectives for different diseases' management, the chemical and biological diversities among the isolated compounds, open promising avenues of research and contribute to renewed interest in these families needing further studies. This review provides an updated overview of their potential as sources of leads for drug discovery, while also highlighting ongoing challenges and future research opportunities.

Stephapierrines A-H, new tetrahydroprotoberberine and aporphine alkaloids from the tubers of Stephania pierrei Diels and their anti-cholinesterase activities

Eight new alkaloids, which are four new tetrahydroprotoberberine alkaloids, stephapierrines A-D (1-4), and four new aporphine alkaloids, stephapierrines E-H (5-8), together with three new naturally occurring alkaloids (9-11) and thirty-four known alkaloids (12-45) were isolated from the tubers of Stephania pierrei Diels. The structures of the new compounds were elucidated by spectroscopic analysis and physical properties. The structures of the known compounds were characterized by comparison of their spectroscopic data with those previously reported. Compound 42 exhibited the strongest acetylcholinesterase (AChE) inhibitory activity, which was more active than galanthamine, the reference drug. Compound 23 showed the highest butyrylcholinesterase (BuChE) inhibitory activity, which was also more active than galanthamine. Molecular docking studies are in good agreement with the experimental results.

Natural potential neuroinflammatory inhibitors from Stephania epigaea H.S. Lo

Stephania epigaea H. S. Lo is a folk medicine widely distributed in the south of China, especially in Yunnan and Guangxi province. An in vitro anti-neuroinflammatory study showed that total alkaloids of it can potently inhibit LPS-induced NO releasing of BV2 cells with an IC₅₀ value of 10.05 ± 2.03 μg/mL (minocycline as the positive drug, IC₅₀ 15.49 ± 2.14 μM). The phytochemical investigation of the total alkaloids afforded three new phenanthrene (1-3), two lactams (4a, 4b), and nine aporphine derivatives (5-13). The final structure of 1 was identified by computer-assisted structure elucidation (ACD/Structure Elucidator software and the ¹³C NMR calculation with GIAO method) due to many possibilities of the substituent pattern. All isolates were evaluated for their anti-neuroinflammatory effects, and as a result, 5, 8, 10, and 11 exhibited stronger inhibitory activities than the minocycline. The results suggested S. epigaea could provide potential therapeutic agents for neurodegenerative diseases.

Research Progress on Anti-Inflammatory Effects and Mechanisms of Alkaloids from Chinese Medical Herbs

As the spectrum of diseases keeps changing and life pace keeps going faster, the probability and frequency of diseases caused by human inflammatory reactions also keep increasing. How to develop effective anti-inflammatory drugs has become the hotspot of researches. It has been found that alkaloids from Chinese medical herbs have anti-inflammatory, analgesic, antitumor, anticonvulsant, diuretic, and antiarrhythmic effects, among which the anti-inflammatory effect is very prominent and commonly used in the treatment of rheumatoid arthritis, ankylosing spondylitis, and other rheumatic immune diseases, but its mechanism of action has not been well explained. Based on this, this paper will classify alkaloids according to structural types and review the plant sources, applicable diseases, and anti-inflammatory mechanisms of 16 kinds of alkaloids commonly used in clinical treatment, such as berberine, tetrandrine, and stephanine, with the aim of providing a reference for drug researches and clinical applications.